Sort lists, add syntax control directives

Author: chorman0773

src/inline-assembly.md

@@ -87,7 +87,7 @@ On x86, the `.intel_syntax noprefix` mode of GAS is used by default.
 On ARM, the `.syntax unified` mode is used.
 These targets impose an additional restriction on the assembly code: any assembler state (e.g. the current section which can be changed with `.section`) must be restored to its original value at the end of the asm string.
 Assembly code that does not conform to the GAS syntax will result in assembler-specific behavior. 
-Further constraints on the directives used by inline assembly are indicated by [Directives Support](#directives-support). 
+Further constraints on the directives used by the assembly are indicated by [Directives Support](#directives-support). 
 
 [format-syntax]: ../std/fmt/index.html#syntax
 [rfc-2795]: https://github.com/rust-lang/rfcs/pull/2795
@@ -481,70 +481,65 @@ To avoid undefined behavior, these rules must be followed when using function-sc
 
 ### Directives Support
 
-Inline assembly supports a subset of the directives supported by both GNU AS and LLVM's internal assembler, given as follows.
+Inline ASM supports a subset of the directives supported by both GNU AS and LLVM's internal assembler, given as follows.
 The result of using other directives is assembler-specific (and may cause an error, or may be accepted as-is).
 
-If inline assembly includes any "stateful" directive that modifies how subsequent assembly is processed, the block must undo the effects of any such directives before the inline assembly ends.
-
 The following directives are guaranteed to be supported by the assembler:
 
 
 - `.2byte`
 - `.4byte`
 - `.8byte`
-- `.byte`
-- `.short`
-- `.word`
-- `.long`
-- `.quad`
-- `.float`
-- `.double`
-- `.octa`
-- `.sleb128`
-- `.uleb128`
+- `.align`
 - `.ascii`
 - `.asciz`
-- `.string`
-- `.skip`
-- `.space`
 - `.balign`
 - `.balignl`
 - `.balignw`
 - `.balign`
 - `.balignl`
 - `.balignw`
-- `.fill`
-- `.section`
-- `.pushsection`
-- `.popsection`
-- `.subsection`
-- `.text`
 - `.bss`
+- `.byte`
+- `.comm`
 - `.data`
 - `.def`
+- `.double`
 - `.endef`
-- `.scl`
-- `.comm`
-- `.lcomm`
-- `.option`
 - `.equ`
 - `.equiv`
 - `.eqv`
-- `.set`
-- `.align`
+- `.fill`
+- `.float`
+- `.lcomm`
 - `.inst`
+- `.long`
+- `.octa`
+- `.option`
 - `.p2align`
-- `.bundle_align_mode`
-- `.bundle_lock`
-- `.bundle_unlock`
-- `.symver`
+- `.pushsection`
+- `.popsection`
+- `.quad`
+- `.scl`
+- `.section`
+- `.set`
+- `.short`
+- `.skip`
+- `.sleb128`
+- `.space`
+- `.string`
+- `.text`
+- `.uleb128`
+- `.word`
+
+
 
 The following directives are guaranteed to be supported for `global_asm` only:
 
 - `.alt_entry`
-- `.private_extern`
 - `.globl`
 - `.global`
+- `.private_extern`
 - `.size`
 - `.type`
 
@@ -592,18 +587,21 @@ On targets with structured exception Handling, the following additional directiv
 - `.seh_stackalloc`
 
 
-##### x86 (32-bit and 64-bit)
+##### x86
 
-On x86 targets, both 32-bit and 64-bit, the following additional directives are guaranteed to be supported:
+On x86, the following additional directives are guaranteed to be supported:
+- `.att_syntax`
+- `.intel_syntax`
 - `.nops`
 
-On x86 for `global_asm!` only, the following additional directives are guaranteed to be supported (it is unspecified whether `.code16` or `.code32` are supported for `asm!()`):
+Use of the `.att_syntax` and `.intel_syntax` with no parameters is supported, but the syntax must be restored to the option at entry (`.intel_syntax` without the `att_syntax` asm option, or `.att_syntax` with that option) or the behaviour is undefined (the output of the compiler may be corrupted as a result). Use of `.att_syntax` and `.intel_syntax` with an option (such as `.intel_syntax prefix` or `.att_syntax noprefix`) is unsupported and results in assembler-dependant behaviour. 
 
+On x86 for `global_asm!` only, the following additional directives are guaranteed to be supported:
 - `.code16`
 - `.code32`
 
 
-##### ARM
+##### ARM (32-bit only)
 
 On ARM for `global_asm!` only, the following additional directives are guaranteed to be supported:
 
@@ -614,8 +612,9 @@ On ARM for `global_asm!` only, the following additional directives are guarantee
 
 On ARM, the following additional directives are guaranteed to be supported:
 
+- `.even`
 - `.fnstart`
 - `.fnend`
-- `.save`
 - `.movsp`
-- `.even`
+- `.save`
+